Paul Reville, former state secretary of education and professor at the Harvard Graduate School of Education, called gubernatorial candidate Jay Gonzalez’s proposal to tax college endowments to raise funds for transportation and education “ spectacularly bad ” on Boston Public Radio Thursday.

Under Gonzalez’s proposal, 1.6 percent would be levied on endowments bigger than $1 billion. Gonzalez estimated that this would bring close to $1 billion a year to the state coffers.

A 1.4 percent tax on the income of endowments that are $1 billion and bigger has already been enacted under the Trump administration's Tax Cuts and Jobs Act. Reville told Boston Public Radio that the difference between Gonzalez’s proposal and the Trump tax is that the Gonzalez tax would be taxing the assets of the endowments not the income.

“The new tax law on Harvard is north of $40 million a year that would be paid whereas, in the case of Gonzalez’s proposal, we’re talking about north of $400 million. It is a huge difference,” Reville said.

A recent WGBH News survey of 1,002 Americans across the country found 50 percent oppose the idea of taxing endowments, while 43 percent support it.

Democrats were against the Trump endowment tax and now Reville is surprised that a Democratic candidate is proposing a more invasive version in Massachusetts.

“Now, we have on our home base, a leading Democratic candidate, former cabinet colleague of mine and friend of mine, who I respect and like as a friend, proposing something you have to think is opportunistic," Reville said. "This is a pot of money that is around. He is being pressured to come up with proposals to fund some very generous thoughts he has about what we should do to improve education and improve transportation. I just think it is the wrong place to go."